This invention relates generally to seating in which the back of the seat includes structure that is aligned with the lumbar region of the seat occupant to reduce back fatigue and more particularly, to a vehicle seat having a mechanically adjustable back support member that is aligned with the lumbar region of the user and is mechanically adjustable to vary the support provided by the back support member. The mounting of the lumbar support member is configured so that the support member has two degrees of freedom of movement to thereby increase the ability of the support member to adapt itself to the support required by each individual seat occupant.
Lumbar supports of the general type embodied in vehicle seats are known, as illustrated by U.S. Pat. No. 4,576,410. However, lumbar supports of this general type that are known do not incorporate the two degrees of freedom advantage obtained by the lumbar support of this intention. Furthermore, the present invention provides an improved cam control for maintaining the lumbar support in adjusted positions. The cam has advantageous characteristics that make it useable in other enviornments. In addition the seatback suspension is integrated with the lumbar support system to prevent a discontinuity in back support from developing when the lumbar system is deployed.